@Ogallala_water: Ogallala Aquifer Summit April 9-10, 2018

High Plains aquifer water-level changes, predevelopment (about 1950) to 2015. Figure 1 from USGS SIR 2017-5040.(Public domain.)

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#Nebraska: Platte River to Republican River compliance transbasin diversion in the plans

From the Associated Press via ARGUS-Press.com:

The plan is to divert excess Platte water via canal, culvert and pipeline over the Platte-Republican divide near Smithfield in south-central Nebraska’s Gosper County and run it south into the Republican via Turkey Creek, the Omaha World-Herald reported.

The 25-mile-long stream is a tributary of the Republican starting about 3 miles west of Smithfield. It empties into the Republican between Edison and Oxford. The Republican River rises in Colorado and crosses southern Nebraska before flowing into Kansas.

The primary objective is to help ensure the state’s compliance with an interstate compact that allocates certain percentages of the Republican River’s flows to Nebraska, Kansas and Colorado, said John Thorburn, general manager of the Tri-Basin Natural Resources District in Holdrege. Although the states have been working in harmony on managing the river in recent years, disputes among the three have escalated to the U.S. Supreme Court.
After three years of active planning, project proponents submitted their initial permit paperwork to the Nebraska Department of Natural Resources last week.

Tri-Basin partnered with the Alma-based Lower Republican NRD to develop the $1.4 million to $1.9 million enterprise known as the Platte Republican Diversion Project. It would tap Platte water from a canal owned by the Holdrege-based Central Nebraska Public Power and Irrigation District. The district stores North Platte River water in Lake McConaughy in western Nebraska and delivers it downstream and into canals for delivery to farmers to irrigate cropland.

“This is precedent-setting for Nebraska,” Thorburn said. “We’d be taking otherwise ‘wasted’ water to be put to good use for a beneficial purpose.”
Thorburn and others expect resistance from environmental organizations that have raised concerns, saying there really isn’t extra water in the Platte and that it’s all precious in providing habitat for endangered bird species, including the whooping crane, piping plover and least tern.

The Platte’s floodwater — the excess flows that would be diverted at times — scrubs trees and other vegetation from sand bars and other important habitat for sandhill cranes. Downstream near Lincoln and Omaha, the river replenishes aquifers and well fields providing drinking water to the state’s two largest cities.

The diversion would not occur during the June-through-August irrigation season, Thorburn said.
The potential economic impact of the project in the Republican basin would range from $14.2 million to $33 million, depending on how much of the water required to meet interstate agreements and obligations comes from the diversion versus other sources, according to a study by the Bureau of Business Research at the University of Nebraska-Lincoln.

The Platte in central Nebraska is designated by the Natural Resources Department as over appropriated, meaning there is more demand for the water than the river can provide. It is the state’s only over appropriated river. Still, there are times when floods funnel high water down the river’s usually shallow channels.

An engineering study by Olsson Associates of Lincoln for the project partners indicated that under two scenarios a potential 57,000 to nearly 140,000 acre-feet of unallocated water could have been diverted from the Platte into the Republican during the period of 2013 to 2016. An acre-foot is the volume of water that would cover an acre of land 12 inches deep.

The peak scenario would require 100 cubic feet per second of water to flow down Turkey Creek at times. A cubic foot is like a box of water measuring one foot by one foot by one foot. It contains around 7½ gallons. This rate of flow is a bit less than the volume of water Omahans see in Big Papillion Creek at Q Street in a typical March.

Turkey Creek’s current base flow is about 12 cubic feet per second. Erosion-control measures and other improvements would allow the creek to handle diverted flows up to 100 cubic feet per second without damaging the surrounding land in Gosper and Furnas Counties, according to the engineering study. The draft application calls for diverting 275 cubic feet per second from the Platte in order to provide up to 100 cubic feet per second into Turkey Creek.

Colorado to pay Nebraska $4M in Republican River settlement

North Fork Republican River via the National Science Foundation.

From the Associated Press (Grant Schulte) via The Colorado Springs Gazette:

The settlement announced Thursday requires Colorado to make the payment by Dec. 31, 2018. Colorado officials did not admit to violating the Republican River Compact, and legislators in that state must still approve the funding.

The agreement seeks to resolve disagreements between the states over Colorado’s past use of water. The Nebraska governor’s office says it will allow both states to continue to work cooperatively.

The settlement bars Nebraska from suing Colorado for alleged violations on or before Dec. 31, 2013.

It was signed by Nebraska Gov. Pete Ricketts and Attorney General Doug Peterson as well as Colorado Gov. John Hickenlooper and Attorney General Cynthia Coffman.

The Republican River’s South Fork near Hale, Colorado, with the region’s seemingly endless fields. Credit: Wikimedia Commons/Jeffrey Beall

From The Courthouse News Service (Ted Wheeler):

Subject to approval by the two states’ legislatures, the payment is due by Dec. 31, with the money earmarked for surface water projects that will bolster water management plans in the basin, Colorado Attorney General Cynthia Coffman said in a statement.

“This settlement provides funds that could be used in the Republican River Basin within Nebraska and creates additional opportunities for cooperative water management between the states,” Colorado Governor John Hickenlooper said.

Nebraska Governor Pete Ricketts echoed the sentiment of cooperation: “Nebraska and Colorado can now continue to focus on providing their water users with greater certainty and to pursue other collaborative opportunities to benefit their shared economies.”

The 452-mile-long Republican River originates in the high plains of Colorado and cuts across sections of western Nebraska and Kansas. The Republican River Compact of 1943 allocates river water for the three states, with 49 percent going to Nebraska, 40 percent to Kansas and 11 percent to Colorado.

The river basin has been a frequent subject of litigation, including a 2014 Supreme Court judgment that ordered Nebraska to pay $5.5 million to Kansas for its own excessive water use upriver.

Colorado officials said the threat of more litigation and its associated costs was a driver in the new settlement. Coffman said the agreement “avoids the costs and uncertainty of litigation and furthers the principles of the compact.”

The region has been relatively free of major drought in recent years, which has helped states stay in compliance despite exponential growth in the number of irrigation wells. According to the United States Drought Monitor, the Republican River Basin region is drought-free or abnormally dry, the least severe drought rating.

But the threat of drought and overuse of groundwater has kept agriculture officials and farmers on edge for years. Nebraska farmers have been suing the state over groundwater for years, in what has become a near-annual tradition.

Steve Nelson, the president of Nebraska Farm Bureau, welcomed the new agreement.

“We applaud the collaborative efforts of both states to address past issues and to work together, putting both parties’ interests on a better path for shared water use,” Nelson said.

Western water law, immensely complicated by decades of litigation in multistate jurisdictions, is further complicated by “use it or lose it” allocations that often discourage conservation.

From The Yuma Pioneer:

The Republican River Water Conservation District’s “compact compliance pipeline” continues to pump ground water into the North Fork of the Republican River near the Colorado/Nebraska state line.

The pipeline first started operating for compact compliance in January 2014. It is part of Colorado’s effort to come into compliance with the Republican River Compact, a 1942 agreement among the states of Colorado, Nebraska and Kansas, concerning water rights along the Republican River.

A stipulated agreement among the three states requires Colorado to send a minimum of 4,000 acre-feet through the pipeline each year. The Republican River Compact Administration groundwater model approved by the three states is used each year to analyze and determine how much more water above the minimum needs to be delivered each year.

Approximately 11,000 acre-feet was delivered into the North Fork in 2017.

The final portion for 2017 was delivered from October through December after the irrigation season was completed.

The pipeline continues to operate as Colorado delivers the 4,000 acre-feet minimum prior to the upcoming growing season.

RRWCD General Manager Deb Daniel said the estimate of how much above the minimum will need to be delivered in 2018 will not be made until September.

Various factors figure into how many acre feet need to be delivered each year — such as the amount of groundwater pumping throughout the Republican River Basin with the amount of precipitation and where it falls within the basin. The more rainfall in Colorado’s portion of the basin can actually increase the state’s obligation to the downstream states.

Daniel noted the state has not had any problems meeting its obligations using the pipeline. Water for the pipeline comes from a series of wells located north of Laird that were purchased by the RRWCD as part of the pipeline project.The appropriation for all of the water rights has been designated to 15 wells within the pipeline project. Currently eight wells are connected and delivering water into the pipeline. In the near future, as the need to off-set depletions and deliver additional water increases, the remaining seven wells will be added to the pipeline system.

Groundwater levels steady in western Kansas, decrease around Wichita — @KUNews

Graphic via the University of Kansas.

From the University of Kansas:

Groundwater levels during 2017, on average, rose slightly or nearly broke even in western Kansas but fell in the Wichita area, according to preliminary data compiled by the Kansas Geological Survey. This was a reversal from 2016 when overall groundwater levels dropped in western Kansas and increased significantly near Wichita.

The KGS — based at the University of Kansas — and the Division of Water Resources (DWR) of the Kansas Department of Agriculture annually measure levels in about 1,400 water wells in western and central Kansas. The collected data are used to monitor the condition and long-term trends of the High Plains aquifer, the state’s most valuable groundwater resource, as well as smaller deep and shallow aquifers.

The High Plains aquifer is a network of water-bearing rocks that underlies parts of eight states and, in Kansas, comprises three individual aquifers—the far-reaching Ogallala aquifer that makes up the majority of the High Plains aquifer, the Equus Beds around Wichita and Hutchinson, and the Great Bend Prairie aquifer in the center of the state. Ninety percent of the measured wells draw from these three aquifers.

Water level changes or stability in the Ogallala aquifer in western Kansas correspond primarily with the amount of water withdrawn for irrigation, which in turn is influenced by the rate and timing of precipitation.

“Much of the western border of Kansas and eastern Colorado saw above normal precipitation patterns in 2017, especially through most of the growing season,” said Brownie Wilson, KGS water-data manager. “As a consequence, water levels were at or above the 2016 levels in much of the region.”

Water level increases in western Kansas mainly occur when the levels in wells rebound as pumping slows. Recharge — water seeping down from the surface — is negligible in western Kansas. In central Kansas, where the aquifer is shallower and average precipitation is higher, recharge can make a difference.

“For areas that have higher local recharge capabilities, such as along and north of the Arkansas River in the Equus Beds and Great Bend Prairie aquifer, precipitation generally influences both pumping and recharge,” Wilson said. “There you can get large swings in declines and rises from year to year.”

The 2017 growing season around the Equus Beds was fairly dry, which led to low recharge and higher withdrawal for irrigation, industry and municipal water supplies. Consequently, the Equus Beds declined nearly 2 feet. The Great Bend Prairie aquifer, which encompasses Great Bend, Kinsley, Greensburg and Pratt, fared better with an increase of about a quarter of a foot.

Most of the wells in the network monitored by the KGS and DWR are within the boundaries of the state’s five Groundwater Management Districts (GMDs), which are organized and governed by area landowners and local water users to address water-resource issues.

In Southwest Kansas GMD 3, average levels dropped just 0.05 feet, the lowest decline there since since the state began administrating the water-level program in 1996. In comparison, the average level fell a total of 23 feet over the previous 10 years.

“Water levels were notably higher in Morton County and along and north of the Arkansas River,” Wilson said. “Still, there were localized areas in the GMD that experienced declines of 1 to 3 feet.”

Even with better overall measurement results in the region for the year, the aquifer is nearly depleted in places.

Wells monitored in GMD 3 are drilled into the Ogallala aquifer except in a few areas where they draw from the deeper Dakota aquifer. The district includes all or part of Grant, Haskell, Gray, Finney, Stanton, Ford, Morton, Stevens, Seward, Hamilton, Kearny and Meade counties.

Another rare water-related event in the region occurred in the summer of 2017 when the Arkansas River flowed in Garden City. The river there has been mainly dry for decades due to high water use and less river flow from Colorado. When there is surface water in the river, it interacts with groundwater in an adjacent shallow alluvial aquifer.

Western Kansas GMD 1 experienced a slight drop of 0.19 feet in 2017 following a 0.55 feet in 2016. Although decreases there have been less drastic than farther south, annual levels have risen only twice since 1996. The GMD includes portions of Wallace, Greeley, Wichita, Scott and Lane counties, where the majority of wells are drilled into the Ogallala aquifer.

Northwest Kansas GMD 4 had an average increase in water levels of 0.33 feet after falling slightly in all but two year since 1996. GMD 4 covers Sherman, Thomas, Sheridan and parts of Cheyenne, Rawlins, Decatur, Graham, Wallace, Logan and Gove counties. Groundwater there is pumped almost exclusively from the Ogallala aquifer and shallow alluvial sources associated with streams.

Big Bend GMD 5 had an average increase of 0.26 feet following an increase of 0.88 feet in 2016. Since 1996, annual levels there rose nine times and fell 13 times. The GMD is centered on the Great Bend Prairie aquifer underlying Stafford and Pratt counties and parts of Barton, Pawnee, Edwards, Kiowa, Reno and Rice counties.

Equus Beds GMD 2, a major source of water for Wichita, Hutchinson and surrounding towns experienced a decline of 1.93 feet, which followed an increase of 2.08 feet in 2016. Since 1996, annual levels there rose nine times and dropped 13 times. The GMD covers portions of Reno, Sedgwick, Harvey and McPherson counties.

“Even with the big declines in GMD 2, this is one of the best years we’ve seen in quite a long time,” Wilson said.

The KGS measures approximately 570 wells in western Kansas each January, and DWR staff from field offices in Stockton, Garden City and Stafford measure about 220, 224 and 360 wells in western and central Kansas, respectively. Most of the wells, spread over 48 counties, are used for irrigation and have been measured for decades.

Measurements are taken primarily in January when water levels are least likely to fluctuate due to irrigation. Infrequently, however, later-than-normal pumping during dry conditions may affect measurement results.

The results are provisional and subject to revision based on additional analysis. Data by well will be available in late February at http://www.kgs.ku.edu/Magellan/WaterLevels/index.html.
The University of Kansas is a major comprehensive research and teaching university. The university’s mission is to lift students and society by educating leaders, building healthy communities and making discoveries that change the world. The KU News Service is the central public relations office for the Lawrence campus.

#NE Supremes: State not liable for delivery shortages due to Republican River Compact compliance

More than 9,000 Landsat images provide vegetation health metrics for the Republican River Basin. Credit: David Hyndman

From The Omaha World-Herald (Joe Duggan):

The Nebraska Supreme Court ruled Friday that the state is immune from lawsuits when compliance with the three-state river agreement reduces the amount of water available for irrigation…

The high court upheld a district court ruling that had dismissed a lawsuit by Rodney and Steven Cappel, who own irrigated farmland in the Republican River valley in south-central Nebraska.

The Cappels showed that from 2013 to 2015 they were blocked from using surface water by the compact because the river was too low. The landowners sued the Nebraska Department of Natural Resources, claiming a constitutional loss of property rights and violation of due process rights. They sought monetary damages and restitution.

Hitchcock County District Judge James Doyle dismissed the lawsuit, saying the landowners did not properly state a claim for relief. The Supreme Court upheld the dismissal, although it ruled the claims couldn’t proceed because the state had not waived immunity to such lawsuits.

Two Republican Basin water projects in #Nebraska get boost from state panel

More than 9,000 Landsat images provide vegetation health metrics for the Republican River Basin. Credit: David Hyndman

From The Hastings Tribune (Andy Raun):

On Dec. 8, the commission announced an award of $2 million to the Nebraska Bostwick Irrigation District for the automation of the Franklin Canal and a grant of $897,300 for the Platte to Republican High Flow Diversion project, which would redirect excess Platte River flows to the Republican River via Turkey Creek in Gosper and Furnas counties.

Both grants were awarded from the state’s Water Sustainability Fund, which was established to assist high-priority conservation projects around the state. They were two out of the five large-project grants (amounts of $250,000 and up) awarded from the WSF, and among 12 total projects that received a combined overall total of more than $10 million in commitments…

According to the grant application form, the Franklin Canal project would allow for timelier and more precise deliveries of water to surface irrigation customers, eliminating average annual spillage of 2,721 acre-feet from the canal plus additional, unmeasured spillage, and allowing water releases from the Harlan County Reservoir to be timed more appropriately for maximum benefit.

The Nebraska Bostwick district, headquartered in Red Cloud, serves water to 22,455 surface-irrigated acres below Harlan County Dam through the Naponee, Franklin, and Courtland/Superior canals. The water is provided by the U.S. Bureau of Reclamation under a long-term contract between the irrigation district and the federal agency.

The Franklin Canal stretches from the north side of the Harlan spillway to about 10 miles east of Red Cloud. Tracy Smith, Nebraska Bostwick general manager, said about 150 customers irrigate a combined total of around 13,000 acres off that canal.

The Natural Resources Commission approved the full $2 million requested for the canal project, which has an estimated price tag of $3.2 million. An additional $1 million has been committed by the LRNRD, with Nebraska Bostwick to cover the remaining $200,000.

Dicke said NRD and Nebraska Bostwick officials have been meeting with the Nebraska Department of Natural Resources to work out details of getting the project built.

Smith said construction activities for the project are expected to take about four months, and that if weather delays and other snags don’t interfere, the newly automated canal will be ready in plenty of time for the 2018 irrigation season.

When the LRNRD board agreed to include $1 million for the work in its fiscal 2017-18 budget, it made the commitment contingent on NDNR agreeing to provide an “acceptable” credit to the Lower Republican district under Republican River Compact accounting for water savings achieved through the investment.

Dicke said the accounting issue will be covered a memorandum of agreement between the NRD and the irrigation district that is being developed to outline how the project will work to everyone’s satisfaction. The NRD board will review the memorandum when it is complete, but Dicke said all parties are anxious to see the project move forward…

Nebraska Bostwick is working with a company called Rubicon Water on the plan to install Rubicon’s Total Channel Control system, or TCC.

Rubicon Water was founded in Australia and does business around the world. The company has a U.S. office in Fort Collins, Colo.

The Nebraska Bostwick project involves installing precise flow measurement and control gates along the length of the canal. The automated gates will be integrated into a radio telemetry network that provides real-time field measurement of water levels and flows at locations all along the canal.

Based on those field measurements, a central computer located in Red Cloud will continually update real-time flow setpoints for each check structure along the length of the canal, matching flows to demand and eliminating spillage.

Smith said both Nebraska Bostwick and Rubicon Water employees are to be involved in the automation project, with Rubicon building and installing 38 structures and installing the computer to run them.

The planned Rubicon project is just the latest of Nebraska Bostwick’s efforts to make water deliveries more efficient…

In an interview, Smith said he was happy to secure the Water Sustainability Fund grant. He said the idea for the Rubicon Water system came from a system already in place in the Frenchman-Cambridge Irrigation District upstream on the Republican.

Smith credited his district board of directors for its interest in pursuing the idea when it came up for discussion last summer…

Colorado, Nebraska, Kansas and the federal government are signatories to the Republican River Compact, a 1943 agreement allocating the waters of the Republican River Basin to the three states through which the river flows.

In times of hydrological shortage, Nebraska is obligated to ensure that Kansas, its downstream neighbor, receives its rightful share of river water. To accomplish this, the Department of Natural Resources can issue a “compact call” requiring the Lower, Middle and Upper Republican NRDs to take extra management steps to offset projected deficits in their beneficial consumptive use of groundwater as compared to their assigned share of the river basin’s virgin water supply.

For the Lower Republican district, those management steps include pumping groundwater toward the river for streamflow augmentation through the Nebraska Cooperative Republican Platte Enhancement project, or N-CORPE.

N-CORPE, which operates a giant wellfield in southern Lincoln County, was established by the Lower, Middle and Upper Republican and Twin Platte NRDs five years ago. When the wellfield is being pumped, each NRD pays whatever share of the pumping costs is commensurate with the accounting credit that district is trying to earn.

Even though the N-CORPE project is in place, the Lower Republican district — which encompasses all of Furnas, Harlan and Franklin counties, plus most of Webster County and southern Nuckolls County — continues to pursue other initiatives that could generate compact accounting credit and reduce the need for pumping in Lincoln County.

Nebraska Bostwick’s Franklin Canal project is one such initiative. Another is the Platte to Republican High Flow Diversion project, or PRD for short, which would divert water from the Platte through the Central Nebraska Public Power & Irrigation District’s E-65 Canal, then release it into the east branch of Turkey Creek at a location between Smithfield and Elwood.

The diverted water would flow about 3,000 feet through a pipeline, then be released into the open creek channel. It would enter the Republican River roughly 25 miles to the south, at a point between Edison and Oxford.

The Platte-to-Republican planning effort is being advanced by an interlocal agency of the same name — a joint venture of the Lower Republican NRD based in Alma and the neighboring Tri-Basin NRD based in Holdrege. The NRDs are working cooperatively with CNPPID, which also is headquartered in Holdrege.

The overall cost of building the project is estimated at $1,495,500, plus $95,000 worth of engineering costs already incurred. According to the WSF grant application, the Lower Republican and Tri-Basin NRDs would provide $141,600 each, and CNPPID would provide $315,000, for a total of $598,200 in funding by those three entities to match the state contribution.

Construction features would include riprap to prevent erosion in 21 locations; nine grade control structures; four new drainage structures; three new culvert crossings; and improvements to seven farm ponds to prevent adverse impacts along the creek.

Dicke said he was gratified to see that the Natural Resources Commission had assigned its top score to the Platte-to-Republican grant application. As with the Nebraska Bostwick project, the commission awarded the full amount of funding that had been requested.

Now, however, the NRDs and Central district are working on the all-important application for a surface water appropriation from the state of Nebraska that they must have in order to operate the project. A surface water appropriation is also is commonly known as a “water right.”

Dicke said putting that application together, and doing it correctly, is the project partners’ current top priority…

Mike Thompson, division head for NDNR’s Permits and Registrations Division, said that in order to proceed with the type of proposed project he understands the Platte-to-Republican to be, the project partners first would need a variance from his department’s director giving them permission to apply for a appropriation in an area subject to a moratorium or stay on new applications.

This variance would be needed, Thompson said, because CNPPID would be diverting water for the Platte-to-Republican project near North Platte, which is in a stretch of the Platte River Basin that has been designated as overappropriated.

If that variance petition were to be granted, Thompson said, the project partners then would officially file their application, and NDNR would issue a public notice in newspapers and on its website inviting any interested parties to file written comments. The application packet would address many issues including whether the diverted water would be put to beneficial use.

Anyone objecting to the application also could pay a small fee and request a public notice on the matter, Thompson said. Alternatively, the NDNR director could call for a hearing on his or her own accord.

The department’s internal review of the application would include consultations with the Nebraska Game and Parks Commission concerning whether the proposed project would have adverse impacts on threatened or endangered species, four of which rely on the Platte River for habitat.

Thompson said that in addition to meeting all the requirements for a normal surface water appropriation, the Platte-to-Republican applicants would need to address a number of additional issues since they are proposing an interbasin diversion, transferring water from one river basin to another…

Dicke said it’s important to note that the potential water right being sought for the Platte-to-Republican project would be only for occasional excess flows in the Platte (up to 100 cubic feet per second, for no more than five days at a time due to erosion concerns) that were not earmarked for any other project — for example, in times when extra water is being released from or passed through upstream reservoirs to prevent flooding.

The water right for the Platte-to-Republican project would be junior to all existing projects and even all future projects on the Platte itself…

Project officials expect the construction required to bring the Platte-to-Republican project online would take about seven months, with the timing to be dictated by when a water right might be granted and other permits could be obtained. Meanwhile, conversations continue with landowners along the creek to obtain the needed easements and maintenance agreements…

One possible need is for a permit from the U.S. Army Corps of Engineers under Section 404 of the federal Clean Water Act, which is required when projects affect public waters in certain ways.

@NSF: How much water flows into agricultural irrigation? New study provides 18-year water use record

Here’s the release from the National Science Foundation (Cheryl Dybas/Val Ostrowski):

Irrigation for agriculture is the largest use of fresh water around the globe, but precise records and maps of when and where water is applied by farmers are difficult to locate. Now a team of researchers has discovered how to track water used in agriculture.

In a paper published in the journal Geophysical Research Letters, the researchers detail their use of satellite images to produce annual maps of irrigation. The findings, the scientists said, will help farmers, water resource managers and others understand agricultural irrigation choices and make better water management decisions.

“We want to know how human activities are having an impact on the environment,” said hydrogeologist David Hyndman of Michigan State University (MSU), principal investigator of the project. “Irrigation nearly doubles crop yields and increases farmer incomes, but unsustainable water use for irrigation is resulting in depletion of groundwater aquifers around the world. The question is: ‘How can we best use water?'”

The paper highlights the need to know when and where irrigation is occurring to effectively manage water resources.

The project focuses on an economically important agricultural region of the central U.S.–the Republican River Basin–that overlies portions of Colorado, Nebraska and Kansas, and provides surface water and groundwater to the High Plains Aquifer. The team found that irrigation in this area roughly doubled between 2002 and 2016.

Water use in this region can be complicated because it is regulated to preserve stream flow into Kansas in accordance with the Republican River Compact of 1942.

“Previously, we knew what farms were equipped to irrigate, but not which fields were actually irrigated in any particular year,” said Jillian Deines, also of MSU and the paper’s lead author. “Our irrigation maps provide this information over 18 years and can be used to understand the factors that contribute to irrigation decisions.”

The researchers used Google Earth Engine, a cloud-computing platform that makes large-scale satellite and environmental data analyses available to the public, to quantify changes in irrigation from year to year–an important finding for farmers, crop consultants and policymakers working to improve the efficiency of irrigation.

Google Earth Engine has been an asset for computing the large number of satellite images needed, the scientists said. “It allows researchers to use consistent methods to examine large regions through time,” Deines said.

The project, which also involves MSU research associate Anthony Kendall, is supported by the joint National Science Foundation (NSF)-USDA National Institute of Food and Agriculture (NIFA) Water, Sustainability and Climate (WSC) program and the joint NSF-NIFA Innovations at the Nexus of Food, Energy and Water Systems (INFEWS) program.

“Knowing what to plant, how much land to plant, and how much irrigation water is necessary to support a crop through harvest has been a challenge for farmers throughout time,” said Tom Torgersen, NSF program officer for WSC and INFEWS. “Farmers can now envision a future where models will provide options to help guide decisions for greater efficiency and crop productivity.”

Program managers at USDA-NIFA said that demand for agricultural products will likely increase in the future, while water for irrigation may decrease due to water quality issues and competitive uses.

The Republican River Basin researchers “leveraged new computing power to handle the ‘Big Data’ of all available Landsat satellite scenes, and developed irrigation maps that help explain human decisions about irrigation water use,” said Jim Dobrowolski, program officer in NIFA’s Division of Environmental Systems. The maps hold the promise, he said, of the ability to make future water use predictions.

A NASA graduate fellowship program award also funded the research.